Refractory Distribution Lines Shoud Be Promoted

Abstract: Under fire conditions, at a predetermined temperature and time, the fire equipment distribution lines should maintain the integrity of the line, should be used with fire performance cables or busbar. The use of performance or with fire retardant properties of the cable or busbar results, just make fire thermal energy can not be passed through to an adjoining space Busway ignite flammable materials (through the wall or floor fire district, although wall or floor to prevent heat transfer has met the requirements, the need to use the installation of fire-wall sleeve to achieve fire performance), but can not guarantee "continuous power supply to meet the needs of fire." So fire Busway or fire cable is not suitable for fire-fighting equipment or emergency power distribution lines to use.

Construction engineering, fire fighting equipment and emergency power supply for fire fighting and people to escape. GB50045-95 "fire protection design of tall buildings" (2005 edition) 9.1.4, GB 50016-2006 "architectural design code for fire protection" 11.1.6 stipulates: "Fire electrical equipment distribution lines shall meet the fire continuous power supply needs ...... "But the few designers on the flame resistance, fire resistance and fire resistance zone can not tell, many projects have only fire performance of the busbar or cable misuse of distribution lines in the fire. Under fire conditions, at a predetermined temperature and time, the fire equipment distribution lines must maintain the integrity of the line, in order to meet the requirements. For different occasions, different equipment, distribution lines and fire resistant refractory temperature there is a difference, but not the lack of fire resistance requirements. The following accordance with the relevant product standards and test methods, analyzing fire resistance and fire performance difference.

On cable in 1991, our country has been a national standard GB / T 13033.1-1991, a new version of 2007 (equivalent to IEC 60702-1:2002), which the fire resistance test in accordance with GB / T 19216.21-2003 " In electric cables under fire conditions - Circuit integrity - Part 21 test "(equivalent to IEC 60331-21:1999) carried out, clear cable fire performance test methods. 2005, China's Ministry of Public Security standard GA / T 537-2005 "busbar trunking systems (busways) fire, fire, fire resistance test methods" on fire resistance test methods are also clearly defined. 2006 GB GB 7251.2-2006 "Low-voltage switchgear and control equipment - Part 2: for busbar trunking systems (busways) special requirements" (equivalent to IEC 60439-2:2000) 7.1.1.5 tolerated in flame spread ( flame retardant), 7.1.1.6 busbar trunking fire board unit (fire resistance), 7.1.1.7 maintain circuit integrity under fire (fire resistance), but also clearly defines the technical Busway fire performance requirements and test methods.

1 Fire resistance test

1.1 Fireproof cable fire test
According to GB / T 13033.1-2007 of 13.8, a "finished cable shall GB / T 19216.21 for fire resistance test." GA 306.2-2007 of 3.1 that has the required fire resistance of fire-resistant cables, refers to a line integrity, smoke tightness, smoke toxicity, corrosion resistance of the cable. Its 6.3 provides a fire, fire two, fire three four lines and fire integrity test according to GB / T 19216.21 method specified (for annealing temperature 750 ℃ ​​~ 800 ℃, recommended for the fire time is 90min ); fire a Class A, Class A fire two, fire three Class A and Class A fire four Circuit integrity by GB / T 19216.21 method specified, but the cable by the fire temperature should be 950 ℃ ~ 1000 ℃.

1.1.1 Specimen Installation
And the same fire resistance test specimen size and the necessary connecting two parts, the total length of the test spray fire test specimen is half the length.

1.1.2 Circuit connection
Sample near the end of the transformer, the neutral conductor and all the protective grounding conductor. All metal shield, bare shield wire should be connected to each other or the metal layer and grounded. The conductors connected to the transformer, excluding the circuit indicated in Figure 1 intended for a protective conductor or neutral conductor of those conductors. If the metal sheath, armor or shield as a neutral conductor or protective conductor should be in accordance with Figure 1 as the neutral conductor or protective conductor is connected.

For single-phase, two-phase or three-phase cables, each phase conductor should be connected to each phase of the output transformer, the transformer on the output of each phase 2A series with a fuse or circuit breaker with equivalent characteristics.

Put the conductors in each group and pick up, and then connected to the output of each phase transformer, transformer output in series on each phase of a 2A fuse or circuit breaker with equivalent characteristics.

Sample away from the other end of the transformer:
- Put a conductor or a group of conductors connected to the load and the pointing device (such as described in Chapter 5) at one end, the other end;
- The neutral conductor and protective conductor connected to the load of all and pointing device (such as described in Chapter 5) at one end and the other end connected to the transformer terminal fuses L1 (or L2, or L3), see Figure 1.

Figure 1 Basic Circuit

1.1.3 Determine the conditions
Line with maintaining the integrity of the cable, as long as the testing process:
- Hold voltage, ie without a fuse or circuit breaker disconnect;
- Conductor constantly, ie without a light bulb goes off.

1.2 GA / T 537-2005 on fire busbar fire resistance test
According to GA / T 537-2005 of 4.3, a "busbar trunking systems (busways) fire resistance test, 4.3.1 and 4.3.2 should also be two trials, two trials are qualified to determine their fire resistance qualified." . 4.3.1 is spray test, 4.3.2 is a fire test.

1.2.1 Spray test

1.2.1.1 Spray Equipment
GA / T 537-2005, the spray test equipment, including heating equipment, nozzles and electrical connection devices.

Heating equipment complies with GB / T 19216.11-2003/IEC 60331-11:1999 the regulations, if a heating device can not meet the requirements of the specimen surrounded by the fire, we can use two sets of heating equipment heating simultaneously on both sides of the specimen .

Standard nozzles, nozzle diameter: 6.3 mm, spray rate: (12.5 ± 0. 625) L / min, nozzle pressure: about 30 kPa (equivalent free jet vertically upward height 2.5 m). Torch and the location of the specimen shown in Figure A.2.
- Blowtorch center plane below the lowest point of the specimen (70mm ± 10mm);
- Nozzle away from the vertical center of the specimen approximately 45mm

Circuit connected devices including transformers, fuses, load and lights and so on, the connection method same as in Figure 1.

Figure A.2 Blowtorch And The Arrangement Of The Specimen </ P>

1.2.1.2 Spray test procedure
a) Heat: lit torch, the horizontal distance from the nozzle is 45 mm, the vertical distance of 70 mm above the position of a diameter of 0.5 mm parallel to the longitudinal axis of the thermocouple and the nozzle temperature of the test flame, adjust the gas supply system, so that the flame maintained at a temperature between 750 ℃ ​​~ 800 ℃, then the burner according to GA / T 537-2005 requirements of A.4.c arranged below the joints of the specimen at the beginning of the heating, the heating time is the specimen of time for the fire resistance test half, is generally 30 minutes.
b) Spray: using a predetermined spray equipment, the specimen between the two bearing parts spray.
c) Power test: after spraying requirements in accordance with the specimen in Figure 1 are connected, turn on the power, the voltage to the rated voltage of the specimen, pressurized 5 min. Observe whether the fuse is blown, the lamp is off.

1.2.1.3 Spray test Note:
a) Heating flame temperature is 750 ℃ ​​~ 800 ℃ (with the manufacturers to choose for fire temperature, currently used for fire 950 ℃ more common).
b) Fitting in the specimen center of the burner flame, and to meet the area surrounded by the fire requirements.
c) Spray time between the specimen by two order partial surface area was calculated per square meter of 1 min, at least 3 min.
d) The specimen from the center of the nozzle vertical distance of 3m (but in order to spray in all directions from the specimen, when necessary, may be appropriate to shorten the distance).

1.2.1.4 Determine the conditions
Spray test, if the following conditions are met, then the line is not the loss of integrity of the specimen spray test qualified.
- Hold voltage, ie without a fuse or circuit breaker disconnect;
- Conductor constantly, that a lamp does not go out.

1.2.2 Fire Test
GA / T 537-2005 "busbar trunking systems (busways) fire, fire, fire resistance test methods" on the fire test test methods.

1.2.2.1 Test Equipment
a) Fire resistance test apparatus shall comply with GB / T 9978-1999 "architectural components resistance test methods" Chapter (new version of GB / T 9978.1-1008 "Test methods for fire resistance of building elements - Part 1: General requirements" in Chapter 5) requirements.
b) Transformer
A three-phase transformer is star-connected transformer or single-phase transformer (group), it should have sufficient capacity to make the maximum allowable leakage current can still maintain the required test voltage.
c) In order to test the integrity of the specimen circuit, should be the necessary electrical connections, the connection diagram shown in Figure 3.

Figure 3 Specimen Electrical Connection Diagram

1.2.2.2 Test conditions
Thermocouple measured a predetermined average temperature of the furnace, according to the following equation and 4, monitor and control its temperature in the furnace:
T = 345lg (8t +1) +20
Where: T - the average furnace temperature in degrees Celsius (℃);
t - Time, in minutes (min).

Figure 4 Standard Time - Temperature Curve

1.2.2.3 Test Procedure

1.2.2.3.1 Trial start and end
After power regulating transformer, and gradually increased to the rated voltage of the specimen and through load configuration of the current passing through the line of 0.25 A. Then the ignition, when the fire test specimen close to the center of the furnace thermocouple temperature reaches 50 ℃, the timer starts working all measuring instruments, testing begins. 1.2.2.5.2 during the test requirements shall be observed. Time for fire should not be less than 30 min, stop for the fire continued to electrify 15 min. The total duration of the test for the fire time plus 15 min cooldown.

1.2.2.3.2 Measurement and observation
a) Test the furnace temperature measurement
Temperature measurement by GB/T9978-1999 implementation of the provisions in 7.3.1.
b) Test furnace pressure measurement
Pressure measurement according to GB/T9978-1999 implementation of the provisions in 7.3.2.
c) Test phenomena observed
Process, always observe the display of fuses and bulbs.

1.2.2.3.3 Determine the conditions
Fire resistance test process, if the following conditions are met, then the line is not the loss of integrity of the fire test specimen qualified.
- Hold voltage, ie without a fuse or circuit breaker disconnect;
- Conductor constantly, ie without a light bulb goes off.

1.3 GB 7251.2-2006 fire busbar technical requirements and test methods
GB 7251.2-2006 "Low-voltage switchgear and control equipment - Part 2: for busbar trunking systems (busways) Special Requirements" 7.1.1.7 stipulates the circuit integrity requirements, "fire-resistant design of busbar trunking unit In case of fire should be kept within the specified time integrity of the line, "" maintaining circuit integrity test methods is still under consideration. " Because at that time there GB / T 19216-2003 "in cables under fire conditions - Circuit integrity" and the 2005 GA / T 537-2005 "busbar trunking systems (busways) fire, fire, fire resistance Test Methods "two related standards, the standard method of the same wiring, the test apparatus and the test methods are different. GA / T 537-2005 detect the average furnace temperature, the temperature continued to rise over time, and 60 minutes to reach the average furnace temperature 950 ℃, 3 hours to reach the average furnace temperature of 1150 ℃; GB / T 19216-2003 detect the flame temperature, heat circulation, the temperature does not rise over time. If you can use GA / T 537-2005 / 60 min test, equivalent to withstand GB / T 19216-2003 for fire 950 ℃, 180 min fire, big gap between the two test methods. Therefore, in 2005 when the revision GB 7251.2-2006 fire line busbar trunking unit integrity test method "is still under consideration." At present, China resistant cables according to GB / T 19216-2003 Test method for test. The fire resistance test fire busbar 3C certification is based on the standard MPS GA / T 537-2005 Test Method Test. 3C certification according to the existing fire through 60 minutes of time trials to meet withstand (according to GB / T 19216.21-2003 test methods) for fire 950 ℃, 180 minutes fire resistance.

2 Fire performance test

2.1 GA / T 537-2005 about fire performance test method

2.1.1 Test device
Building components shall comply with GB/T9978-1999 resistance test methods specified in Chapter 4.

2.1.2 Test conditions

2.1.2.1 Temperature conditions
Building components shall comply with GB/T9978-1999 resistance test methods specified in 5.1.

2.1.2.2 Pressure conditions
Building components shall comply with GB/T9978-1999 resistance test methods specified in 5.2.

2.1.2.3 Under fire conditions
Specimen is surrounded by the fire, the actual project except with special requirements.

2.1.3 Specimen Requirements
Fire straight busbar trunking unit length of 1800mm.

2.1.4 Installation
Test specimen supporting structure can be used precast concrete slab or brick. According to the actual installation in the building, the specimen mounted on the support structure inside holes reserved. Specimens should be in the test apparatus pressure area, away from the test device from both sides and the upper side of not less than 200mm; when multiple simultaneous test specimen, the specimen should be less than the distance between the 200mm. The fire resistance of the support structure should meet the requirements of fire resistance test piece.

Reserved holes on the support structure and the test piece with a non-flammable insulating material gap sealing, the test piece end to fire a non-flammable insulation material sealing and wrapping, wrapping the length of the specimen of the same thickness as the support structure.

Specimen horizontal mounting in Figure 5, Figure 6 installed vertically.

Figure 5 Schematic Horizontal Mounting Specimens

Figure 6 Specimens Vertical Installation Diagram

2.1.5 Test Procedure

2.1.5.1 Trial start and end
Before the start of the trial record the ambient temperature. When the fire test specimen close to the center of the furnace thermocouple temperature reaches 50 ℃, all measuring instruments started working trial began. During the test requirements of 2.1.5.2 shall be observed. If you lose during the test fire integrity and / or fire-resistant insulation, the test can be terminated. If you do not lose the fire integrity and insulation, but has reached the expected requirements, but also may terminate tests.

2.1.5.2 Measurement and observation
a) Test the furnace temperature measurement
Test furnace temperature measurement by GB/T9978-1999 implementation of the provisions in 7.3.1.
b) Test furnace pressure measurement
Test furnace pressure measurement according to GB/T9978-1999 implementation of the provisions in 7.3.2.

2.1.5.3 Determine the conditions
In a certain period of time, if the specimen fire integrity and insulation to meet the requirements, then determine the fire performance qualified.
Fire integrity lost by GB/T9978-1999 determine the conditions in 8.1.a regulations.
Loss of fire-resistant insulation judgment conditions:
Specimen fire back surface average a temperature rise exceeding 140 ℃ and / or back fire test piece internal temperature exceed 180 ℃, then that specimen loses fire-resistant insulation.

2.2 GB7251.2-2006 on the fire performance test method

7.1.1.6 Busbar trunking fire board unit
If the horizontal or vertical busbar trunking systems through architecture barrier (such as a wall or floor) busbar trunking fire board unit should be designed to prevent the spread of flame in the fire, test methods and test according to ISO 834-1:1999 conducted with GB / T 537 -2005 fire performance tests like test methods.

GB7251.2-2006 on the fire performance test method is as follows:
Building structure fire performance verification
The test is applicable to this design to prevent spread of flame across the building busbar trunking. Test according to ISO834-1: 1999 for. Refractory time was 60min, 120min, 180min or 240min.

Figure M3.1 Used To Verify The Fire Resistance Test Bench (see ISO834-1: 1999)

Determine the conditions:
In a certain period of time, if the specimen fire integrity and insulation to meet the requirements, then determine the fire performance qualified.
Fire integrity lost by GB/T9978-1999 determine the conditions in 8.1.a regulations.
Loss of fire-resistant insulation judgment conditions:
Specimen fire back surface average a temperature rise exceeding 140 ℃ and / or back fire test piece internal temperature exceed 180 ℃, then that specimen loses fire-resistant insulation.

Standard Test Method on the above summary:
Different fire retardant properties. Flame is extinguished after the departure of the fire source. Fire performance under fire conditions is not passed through the busbar or cable heat to another room or another floor, a flammable material near the cable or busbar when ignited other materials. Said fire performance. Because most flammable materials close to 200 degrees will ignite, so the detected temperature limit of 180 degrees.

Conclusion

Fire-fighting equipment and emergency power supply in case of fire to indicate the need to maintain continuity of supply and fire fighting personnel escape fire sprinkler pump equipment startup and standby emergency power, fire resistance so only to meet the needs of the distribution lines.

Main function is to fire performance cables or busbar through the building, partitions, such as a wall, floor or the floor, in a room on fire should not be passed through the heat to another room or another floor, ignite other combustible materials resulting in another room or another floor on fire, so the fire performance suited to use fire power distribution lines.

Non-flammable, non-flammable stated that some norms can also be used for fire distribution lines, much less clear, power transmission lines fire, fire, fire belong to non-flammable, non-renewal of the combustion flame retardant, fire is Anti-heat transfer, distribution lines only truly adapt fire resistance fire.

To our scientific and technological development and people's lives and property safety, the specifications and design drawings should clearly different distribution lines should be used in different fire fire performance power transmission lines, to meet the needs of different places to be marked fire temperature and fire resistance .


References
[1] Tianjin Institute of Electric Drive. GB 7251.2-2006 / IEC 60439-2:12000 Low-voltage switchgear and control equipment - Part 2: for busbar trunking systems (busways) the special requirements of [S]. Beijing : Standards Press of China, 2006.
[2] Ministry of Public Security Sichuan Fire Research Institute. GB 50045 - 95 fire protection design of tall buildings (2005 edition) [S]. Beijing: China Planning Press, 2005.
[3] Ministry of Public Security, Tianjin Fire Research Institute. GB 50016 - 2006 architectural design code for fire protection [S]. Beijing: China Planning Press, 2006.
[4] Shanghai Electric Cable Research Institute. GB / T 13033.1 - 2007 / IEC 60702-1:2002 rated voltage 750V and below Mineral insulated cables and their terminations - Part 1: Cables [S]. Beijing: Standards Press of China, 2007.
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[6] Shanghai Electric Cable Research Institute. GB / T 19216.21-2003 / IEC 60331-21:1999 on electric cables under fire conditions - Circuit integrity - Part 21: Test procedure and requirements for rated voltages 0.6/1.0kV and the following cables [S]. Beijing: Standards Press of China, 2004.
[7] Tianjin Fire Research Institute of Ministry of Public Security. GB / T 9978.1-2008 Test methods for fire resistance of building elements - Part 1: General requirements [S]. Beijing: Standards Press of China, 2009.
[8] Tianjin Fire Research Institute of Ministry of Public Security. GA / T 537-2005 busbar trunking systems (busways) fire, fire, fire resistance test methods [S]. Beijing: Standards Press of China, 2005
[9] Ministry of Public Security Sichuan Fire Research Institute. GA 306.2-2007 fire retardant and fire resistant cables Cables [S]. Beijing: Standards Press of China, 2007.